gdb: update ranged_breakpoint::print_one_detail in comments

The print_one_detail_ranged_breakpoint has been renamed to
ranged_breakpoint::print_one_detail in this commit:

  commit ec45bb676c9c69c30783bcf35ffdac8280f3b8bc
  Date:   Sat Jan 15 16:34:51 2022 -0700

    Convert ranged breakpoints to vtable ops

So their comments should be updated as well.